620 AXNT20 KNHC 200439 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 0615 UTC Fri Dec 20 2024 Tropical Weather Discussion for North America, Central America Gulf of Mexico, Caribbean Sea, northern sections of South America, and Atlantic Ocean to the African coast from the Equator to 31N. The following information is based on satellite imagery, weather observations, radar and meteorological analysis. Based on 0000 UTC surface analysis and satellite imagery through 0355 UTC. ..MONSOON TROUGH/ITCZ... The monsoon trough enters the Atlantic through the coast of Liberia near 06N10W and extends westward to 05N20W. The ITCZ stretches from 05N20W to 04N35W and to NE Brazil near 03N51W. Scattered moderate convection is observed from 03N to 08N and between 27W and 36W. ...GULF OF MEXICO... A cold front extends from west-central Florida near 27N82W to 26N90W, then becoming a stationary front to southern Tamaulipas near 22N98W. No significant convection is noted with this boundary. However, areas of marine fog are affecting portions of the northern and eastern Gulf waters. Visibility may decrease below 1 nm and mariners are advised to use caution. High pressure dominates the remainder of the Gulf of Mexico, resulting in moderate to fresh N-NE winds in the south-central Gulf and Bay of Campeche. Seas in these waters are 3-5 ft. Moderate or weaker winds and slight seas prevail elsewhere. For the forecast, the aforementioned front will slowly progress southeastward tonight before weakening on Fri across the southern Gulf, and dissipating near the Yucatan Channel on Sat. Moderate to locally fresh N to NE winds will prevail across the basin through Fri. A reinforcing cold front will progress southeastward through the northern and central Gulf Fri night through this weekend. Fresh to locally strong N winds will be possible along and behind this front in the northern Gulf Fri night. Moderate NE to E winds are then expected this weekend into early next week as the fronts weaken and ridging builds over eastern Mexico. ...CARIBBEAN SEA... Scattered showers are occurring in the north-central and SW Caribbean waters, while generally drier conditions are found elsewhere. A strong subtropical ridge over the NE Atlantic extends southwestward into the basin, supporting fresh to strong NE winds in the south-central Caribbean. Seas in these waters are 6-9 ft. Moderate to fresh easterly trade winds and seas of 6-9 ft are noted in the north-central and eastern Caribbean. The highest seas are associated with long period northerly swell entering the NE Caribbean through Atlantic passages. In the rest of the basin, moderate or weaker winds and slight to moderate seas are prevalent. For the forecast, fresh E to NE winds will prevail across the south- central through eastern Caribbean, as well as through the Atlantic Passages through Fri morning as a strong pressure gradient prevails between the Colombian low and high pressure in the central Atlantic. Pulsing strong winds in the Gulf of Venezuela and offshore of northwestern Colombia will occur into Fri morning, and locally rough seas will be possible near these winds. Moderate to locally fresh NE to E winds will dominate the basin Fri through this weekend as ridging builds over the Caribbean. Looking ahead, high pressure in the central Atlantic will slowly move eastward early next week and a series of cold front will move off the southeastern United States. A building pressure gradient between these features will lead to fresh to locally strong NE to E winds across much of the Caribbean. ...ATLANTIC OCEAN... A cold front extends from a low pressure off the Carolinas to east-central Florida, while a surface trough is analyzed across the central Bahamas to eastern Cuba. Divergence aloft supports scattered showers east of the surface trough to 69W. The remainder of the SW North Atlantic, west of 55W, is dominated by a strong subtropical ridge over the NE Atlantic. A recent scatterometer satellite pass captured moderate to locally strong easterly winds over much of the basin, especially between 55W and 75W. Rough seas are occurring in the area described, peaking around 11 ft near 22N55W. Marine fog is occurring in the waters off NE Florida and visibility may decrease below 1 nm. Mariners are urged to use caution navigating these waters. Farther east, a 1015 mb non-tropical low pressure system is centered near 32N42W and a cold front extends south from 31N36W to 19N42W. Scattered showers and isolated thunderstorms are evident ahead of the frontal boundary to within 120 nm. Fresh to strong southerly winds are noted on satellite-derived wind data north of 20N and east of the frontal boundary. Seas in the area described are 7-10 ft. Fresh to near gale-force N-NW winds and seas of 10-15 ft are found north of 29N and between 42W and 48W. The ridge also sustains fresh to strong easterly winds in the central Atlantic, especially south of 28N and between 45W and 55W. Seas in these waters are 7-11 ft. Satellite images depict an outbreak of Saharan dust over the eastern Atlantic and this dry airmass will continue moving westward over the next few days. Elsewhere, moderate or weaker winds and moderate seas are prevalent. For the forecast W of 55W, widespread fresh to locally strong E to NE winds occurring north of 15N and east of the Bahamas will slowly diminish through Fri as high pressure in the central Atlantic weakens and shifts eastward. Rough seas in the aforementioned region will slowly subside from north to south through early Sat. A cold front extending from central Florida to 31N76W will decrease in forward speed through Fri before reaching from 31N68W to western Cuba by Sat morning, then weaken from 31N59W to near the Windward Passage Sun morning. Fresh to strong W to NW winds and rough seas will occur behind the front N of 28N. Looking ahead, widespread fresh to locally strong NE winds and rough seas will redevelop across areas north of 20N Sun night through early next week as strong high pressure builds across the region behind the weakening front. $$ Delgado